Rotary shell fuze



Feb. '27,V 1962 H. JUNGHANS ETAL 3,0225733 RQTARY SHELL FuzE Filed April24, 1959 4 sheets-sheet 1 NVENTORJ /fTjzfTzjsrm v Weef- Feb 27, 1952 H.JUNGHANS ETAL 3,022,733

ROTARY SHELL FuzE Filed April 24. 1959 4 Sheets-Sheet 2 'Ffa f( 19 l 70pH fi @mu 1 .i i!

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ROTARY SHELL FUZE Filed April 24, 1959 4 Sheets-Sheet 4 3,922,733Patented Feb. 27,1962

3,022,733 RTARY SHELL FUZE Helmut Junghans, Rekenhof, Schramberg-Sulgen,Germany, and Rudolf Weber, Untere Schillerstr. Z4, Schramberg, Germany i1 Filed Apr. 24, 1959, Ser. No. 80%,624

Claims priority, application Germany Apr. 25, 1953 The invention relatesto a rotary shell fuze with sensitive impact ignition and aself-destroying device dependent upon the numbeiyof revolutions. Theobject of the invention is to produce a self-destroying system for whichthe weakest possible self-destroying spring is required, because in theknown systems the objection has been found that a strong self-destroyingspring, which as is known is fitted under pretension, becomes sluggishand fatigues in the course of time. The invention is characterized inthat centrifugal levers of the self-destroying device are pivotableabout axes which lie in a plane at right angles to Vthe axis of rotationof the fuze so that the inwardly directed radial arms of these leverscan act in the tiring direction on a-pressure surface provided on thefiring .pin when liberated by a timing mechanism arranged under andsupporting them, andrthat above these centrifugal levers the springofthe self-destroying device cooperating with the backs of these leversis arranged in the fuze head, the adjustment of the self-destroyingsystern being such that in the initial safety position the center ofgravity of a centrifugal lever lies above the plane determining itspivot axis which it traverses in the point of self-destruction.

The arrangement according to the invention of centrifugal levers betweenthe pretensioned spring of the selfdestroying device and the firing pin,presents the advantage that the centrifugal force participates andassists in the forward thrust of the tiring pin and as a result thespring of the self-destroying device can be kept correspondingly weakerand its pretension be less, whereas in the known systems the/springs ofthe self-destroying device have to be stressed to the maximum limit ofelasticity on account `of the limited structural space available. In thepreferred embodiment of the invention Va centrifugal spiral is employedfor'temporarily locking the centrifugal levers of the self-destroyingdevice.. A simple form of construction of the fuze is obtained if thecentrifugal levers of the self-destroying device are mounted with theirpivot axles in open bearings which are formed by recesses in the fuzehead and/or in the fuze base, and slotted plates are provided forlaterally guiding these centrifugal levers, which plates cover theabovementioned recesses. The spring of the self-destroying devicepreferably cooperates with the centrifugal levers through theintermediary of a wide flanged sleeve, whereby the lever arms at thesepoints of engagement are shorter than those acting on the firing pin,preferably one-third to one-quarter thereof.

According to another feature. of the invention the striker ram, insteadof being rigidly connected with the firing pin in the strikingdirection, can be freely movable independently thereof and soconstructed that in striking it encounters the centrifugal leversof theselfdestroying device, that is drives the firing pin into the ignitionpellet indirectly through the intermediary of these levers. With thisconstruction a certain delayed action is attained as compared with thenormal constructionwhich is likewise possible in the presentinstance-where the striker ram and the tiring pin are rigidlyinterconnected. In the case of some purposes for which the shells hereunder consideration are used, a certain delay is desirable'whendetonation is dependent upon impact, be-

- spring` Ztl.

cause the shell should only explode after it has `penetrated the targett 1 Other features and advantages of the invention will become apparentfrom the several embodimentshereinafter described by way of example-fromthe drawings and from the claims.

The drawings showthese embodiments on a consider- Fre. 2 is atententaken on une n n of FIG. 1;-

FIG. 3 is a part longitudinal section showing a different Way ofmounting Ithe centrifugal levers of the selfdestroying device;

FlG. 4 shows the second forrn'of construction in longitudinal section online IV--IV of FpIG. 5,'the functional parts being indicated in asimilar manner to that used in FlG.,-l, and

FIG. 5 is a section taken on line V-V of FIG. 4. In the case of thefirstembodiment illustrated in FIGS.' 1 and 2, the -fuze base is,designated by 10, the fuze cap by 11, the striker ram by 12, the firingpin by 13 which` i pierces an ignition pellet which is not shown in thedrawing but which is to be screwed into the compartment 10a. In a recess10b formed in the fuze base a centrifugal safety spiral 11i-'of knowntype is arranged andserves as bore-safe and projection-safe fuze. Aslong as the centrifugal lspiral 14 is Wound tightly around the core 15,the collar 15a of the winding core 15 rests on a thin disk \16 above thecentrifugal spiral 14. The disk 16`serves for protecting the centrifugalspiral against damage under high tiring pressures and may therefore beomitted under favorable circumstances. The firing pin 13 is inserted inthe Winding core. 15 until its collar .13a rests on the core. lt can beseen that the upper end 13b of the pin shaft is free in the bore 12a'ofthe striker ram 12; consequently movement of the striker ram 12 in thepiercing direction cannot be directly transmitted to the firing pin. Theobject of this arrangement will be Vhereinafter' described. The inwardlyprojecting annular step 10c extendsfrom the recess lllbjin upwarddirection; which' together with the peripheral surface of the recess 10dserve as'supporting bearing for the centrifugal levers 18 oftheselfdestroying device. The lateral guiding of these centrifugal levers18 is effected partly by slots 105e formed in the edge of the fuze base10 and partly by guide slots 19a in a guide plate 119 fitted in theupper edge of the fuze base 10. l

The arms 18a of the centrifugal levers 1S project radially inwards andtheir noses 18h can rest on the upper side 15b of the winding core 15rigidly connectedvwith the tiring pin 13. At the same time the backs18e' of the leverl arms 18a are located in the striking range of the endface 12b vof the striker ram 12. Another arm 18d of the centrifugallevers 18 rests on the disk 16 which is inserted between the collar 15aon the windin core and the centrifugal spiral 14.

The spring 20 of the self-destroying device is fitted in a bore 11a inthe fuze cap and the sleeve 7.1 is guided in a widened portion 11b ofthis bore. This sleeve 21 has a wide flange 21a which bears against thepressure points or projections 18e v,under the pressure exerted by theIt willbe seen from the drawingthat the lever arms at these pressurepoints are much shorter than the effective lever arms with which thecentrifugal levers engage the primer.

The construction, arrangement and adjustment of the centrifugal leversis so chosen that in safety position (see FIG. 1, solid lines) thecenter of gravity of the levers in the positions S1 is located above theimaginary plane extending through the pivot axles 17 of the levers andin such a manner that the initial speed of rotation of the shell isstill suicient to overcome in conjunction with the centrifugal forceacting on the centrifugal levers, the force of the pretensioned springof the self-destroying device and to lift the sleeve 21 slightly.

During this stage the centrifugal spiral 14 can fly out into theposition shown in broken lines so that the disk 16 loses its support.

As the number of revolutions decreases, the system enters the state ofequilibrium; the position of the center of gravity is then designated byS2. In the event of irnpact in this state, the striker ram 12 wouldfirst be forced inwardly independently of the ring pin 13, its strikingsurface '12b would then come into contact with the backs of the leversat 18C, carry these along and through their intermediary when the noses18b come into contact with the winding core at 15b, drive the tiring pin13, which is rigidly connected therewith, into the ignition pellet.Thereby three forces act jointly, namely the force caused on the strikerram 12 by the impact, the centrifugal force acting on the levers afterpassing the state of equilibrium and the force of the spring of theself-destroying device.

If the shell misses its target, the state of equilibrium between thecentrifugal force acting on the centrifugal levers of theself-destroying device and the pretension of the spring ofself-destroying device continues to change as the number of revolutionsof the shell decreases, in the sense that the centers of gravity of thecentrifugal leversv 18 are forced out of the state of equilibrium S2 andthe effective centrifugal forces can force the levers 18 downwards asthe lever arm increases in length, so that, shortly after leaving theposition of equilibrium, their noses 18b come into contact with thewinding core 15 and, assisted by the spring 20- of the self-destroyingdevice, drive the firing pin 13 into the ignition pellet with increasingspeed.

As can be seen from FIG. 3, the centrifugal levers of theself-destroying device, which are here designated by 28, instead ofbeing pivotally mounted on pins vor axles, are provided with roundedsupporting arms 28a. With the aid of these supporting arms they bearpartly on the bottom surface 10g of slots `10g worked in the edge of thefuze base 10 and partly against the recess 111ein the fuze cap 11.

In the embodiment illustrated in FIGS. 4 and 5, the self-destroyingsystem of the first embodiment is retained. The dilference is that theimpact does not act indirectly through the intermediary of thecentrifugal levers of the self-destroying device 18, but directly. Thatis, the striker mushroom 50'is rigidly connected with the firing pin 51in: the direction of thrust. Instead of the winding core 1S of the rstform of construction, the firing pin is in this instance provided with acollar 51a which is recessed at 51b so as to receive a half-disk 52.This half-disk 52 is in turn introduced through a lateral slot 53a inthe winding sleeve 53 so far that the centrifugal band 14 is woundsmoothly on the sleeve 53. This arrangement is known per se. The case inquestion is constructed so that the centrifugal levers of theself-destroying device also bear directly ony the centrifugal bandwinding without any disk being interposed.

The self-destroying arrangement operates in the same manner as in thefirst embodiment, that is, after the initial flying out of the windingband 14 and of the safety half-disk 52, the centers of gravity of thelevers, when the target isV missed and the number of revolutions of theshell decreases to a predetermined figure, pass out of the l safetyposition S1 through their labile central position (not shown) andcontinue to move, the force of the spring of the self-destroying devicebeing supplemented by the centrifugal force, until finally their arms18a contacting the end face 51C of the ring pin 51 entrain this untilthe ignition pellet is pierced. The responsive blow takes place withoutthe cooperation of the centrifugal levers 18 in that the centrifugalforce acting on the striker mushroom 50 is directly imparted to thetiring pin 51.

In the second embodiment only two centrifugal levers are providedinstead of three; these levers are laterally guided in the slotted plate54, FIG. 5.

We claim:

1. A rotary shell self-destroying fuze comprising a base havingl arecess therein and a central axial opening, a fuze cap mounted on thebase and having a bore therein, a core mounted in the central axialopening and having an axial bore therein, a ring pin in the fuze cap andextending through the axial bore in the core, a guide plate in the fuzecap and having a plurality of spaced and radially arranged slotstherein, a centrifugal lever rotatably mounted in each slot with a pivotpoint near the outer peripheral edge of the fuze base, each lever havingan upper arm and a projection and a lower arm, a safety coil springnormally coiled around the core and in this position forming an abutmentfor the lower arms of the centrifugal levers, and a sleeve mounted inthe bore of the fuze cap and having a flange to contact the projectionsof the levers, said spring flying radially due to centrifugal force topass from under the levers to force the upper arms of the levers tocontact the core to permit the sliding actuation of the firing pin.

2. A yfuze according to claim 1, in which the centrifugal levers aremounted in the slots with play, and guided by the slotted plate insertedin the fuze.

3. A fuze according to claim l, in which an inner shoulder is mounted inthe fuze base serving as a bearing for the centrifugal levers, and inwhich pivot pins are provided one for each centrifugal lever.

4. A fuze according to claim 1 in which the radial slots provided in theguide plate of the fuze base serve as lbearings for the centrifugallevers and the slots being covered on one side Vby the inner wall of thefuze cap.

5. A fuze according to claim 1, in which the lever arm between the pivotpoint of each centrifugal lever and the engagement point of the sleevewith the projection being smaller than the upper arm of the centrifugallever and ranging from one-third to one-quarter of the length of thelatter. y

6. A 4fuze according to claim l, in which a cover disk is provided onthe coil spring to support the centrifugal levers by contact with thelower arms when the spring is tightly wound around the core.

7. A fuze according to claim 1, in which a striker ram is provided inthe cap for the firing pin and contacting the projection of each of thecentrifugal levers.

References Cited in the file of this patent UNITED STATES PATENTS1,3'66,l48 Zeid'ler Jan. 18, 1921 2,014,393 Mathsen Sept. 17, 19352,782,717 Burri Feb. 26, 1957 2,790,390 Baker Apr. 30, 1957 2,8t18,812Shenk Jan. 7, 1958 2,873,678 Koonz Feb. 17, 1959 2,924,176 Neuwinth Feb.9, 1960 FOREIGN PATENTS 61,219 Denmark July 26, 1943

